A light emitting device (LED) is a p-n junction diode having a characteristic in which electric energy is converted into light energy, and may be formed by compounding Group III and Group V elements on the periodic table. An LED may represent various colors by adjusting a composition ratio of a compound semiconductor.
In a LED, when a forward voltage is applied, electrons of an n layer are combined with holes of a p layer, and energy corresponding to band gap energy between a conduction band and a valence band may be generated, and when the energy is emitted in the form of light, the LED functions.
For example, a nitride semiconductor has received a great interest in a development field of an optical device and a high-output electronic device due to high thermal stability and wide band gap energy thereof. In particular, a blue LED, a green LED and an UV LED using the nitride semiconductor are commercialized and used widely.
The LED may be classified into a lateral type and a vertical type depending on a location of an electrode.
A lateral type LED among LEDs according to the related art is formed such that a nitride semiconductor layer is formed on a substrate and two electrode layers are disposed on an upper side of the nitride semiconductor layer.
Meanwhile, recently, light emitting devices have been applied for various IT devices and mobile phones, and a small LED chip has been adopted as a light emitting device for IT devices and mobile phones. For example, recently, a small lateral LED chip has been adopted for mobile phones.
Meanwhile, since the distance between an n-electrode and a p-electrode is limited according to the restriction of the size of a LED chip for mobile phones in the related art, there is a technical problem that design of a distance between electrodes considering a current spreading length is not reflected.